Electromedical apparatus



Oct. 13, 1931 v M. SMART 1,827,045

ELECTHOMEDICAL APPARATUS Filed Jan. 51, 1930 5 Sheets-Sheet 1 Z ,POWERLJNEs v I 1- 2 55+ i459 TO PATIENT MORTON 5MHE7;

Oct. 13, 1931. M. SMART ELECTROMEDICAL APPARATUS Filed Jan. 31. 1950 '3Sheets-Sheet 2 1520676507: y ffo/ero/v 5/7457;

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0a. 13, 1931. M. S MART ELECTROMEDICAL APPARATUS Filed Jan, 31, 1930 3Sheets- Sheet 3 I NORTON 5/7HE7', m 4/$/?/0/Wey.

Patented Oct. 13, 1931 PATENT OFFICE I MORTON SMART, OF LONDON, ENGLANDELEGIROMEDICAL APPARATUS Application filed January 31, 1930. Serial No.425,030.

This invention relates to electro medical apparatus and has for itsobject the provision of apparatus capable of producing painlessgraduated muscular contraction under complete control of the operator.

It is well known that the secondary current produced by anordinary-inductioncoil with the usual type of make and break, producesspasmodic movement of the muscles when apm plied to the human body, andis therefore incapable of use for fractures and unadvisable for mostother muscular remedial measures.

The present invention has for its object the provision of an apparatuscapable of pro ducmg painless graduated muscular contraction undercomplete control of the operator by means of alternating current of aspecial form hereinafter described.

The apparatus of this invention consists broadly of an induction coilhaving a variable inductive coupling between the primary and secondarycircuits and is provided with a make and break device which breaks theprimary circuit gradually so that the average rate of collapse of thefield due to each inter ruption of the primary is substantially equal tothe average rate of growth thereof.

In the drawings:

Figure 1 is a diagrammatic view of the apparatus.

Figure 2 is a plan of the coil of the apparatus, partly in section.

Figure 3 is a sectional view taken on the line III--III of Figure 2.

Figure 4 is a similar view taken on the line IVIV of Figure 2.

Figure 5 is a sectional elevation of the interrupter.

Figure 6 is a sectional View through the interrupter taken on the lineVI-VI of F igure 5.

Referring more particularly to the drawings the numeral 2 designates abase plate on which is .mounted a motor 3 coupled by a flexibleinsulated coupling 4 to a mercury interrupter 5. i A sliding rheostat 6is mount ed on the base 2 and is connected in the motor circuit tocontrol the speed of the motor.

A panel plate 8 carries an inductance coil 9 comprising a primarywinding 10, a secondary winding 12, and a sliding core 13. The primarywinding 10 consists of double cotton covered copper wire of No. 18standard wire gage, equivalent'to .048 inch diameter of bare conductorhaving a resistance of 13.3 ohms per one thousand yards. lVhen wound onthe bobbin or spool 14 the wire should give 17.2 turns per inch. Tappingwires 10 of double silk covered wire of No. 23 standard Wire gage,equivalent to .024 inch diameter,- are brought out from the ends of eachlayer and taken to the soldering tabs 15 under the binding screws 16 onthe ends of the bobbin or spool flanges or ends 17. The ends of thebobbin or spool are slotted to receive the tapping wires, as at 18.

The primary winding 10 is covered by a completel layer of insula-tedsilktape 10".

The secondary winding 12 consists of double silk covered copper wire ofNo. 30 standard Wire gage, equivalent to .0124 inch diamcter of bareconductor having a resistance of 199.15 ohms per one thousand yards.\Vhen wound, the wire should give 67.1 turns per inch. The end of eachlayer of the secondary winding 12 is looped up to form taps 12 andconnected to soldering tabs 15 under binding screws 16 on the ends 17 ofthe spool 14. Each layer of the secondary winding 12 is separated by alayer of insulating tape 20 and the complete coil is finished off bycovering the secondary winding with a layer of tape 21 cemented inplace.

The binding screws 16, to which the taps 10 and 12 are connected, areconnected by suitable leads to contacts 23 of contact switches havingsliding contacts 24.

The sliding core 13 of the coil 9 is composed of laminated wire mountedin an insulating tube 81 having a handle 82 and adapted to be insertedand withdrawn 'from the coil to vary thesecon'dary or induced curofmercu VII 30. The mercury is adapted to be filled into the chamberthrough a filler member 31 mounted in the end plate 27 and normallyclosed by a cap 32.

The end plate 25 is provided. with a central aperture 33 in which aninsulating bushing 34 of bakelite or the like is mounted. The bushing 34is provided withl a flange 35 which abuts the outer face of the plate25, and with a tubular nose portion 36 which projects within the mercurychamber and serves to support and prevent whipping of a contact spindle38. A metallic sleeve 39 is mounted in the bushing 34 and projectsoutwardly therefrom to form a support for the spindle 38. The sleeve 39is provided with a flange 40 which overlies the flange 35 on the bushingand is secured in position by screws 41.

Suitable anti-friction bearings 42 are mounted in the sleeve 39 and thespindle 38 is journaled therein.

An insulating sleeve 43 is fitted on the spindle 38 and extends fromadjacent the forward end of the spindle rearwardly into the sleeve 39.The forward end of the spindle 38 is squared, as at 44, and has a doubleended contact blade 45 mounted thereon. A short thimble 46 of insulatingmaterial is fitted over the end of the spindle and a nut 47 is threadedon the spindle and serves to force the thimble 46 against the contactblade 45 and to thereby clamp the blade in position between the thimble46 and sleeve 43.

A suitable splash plate or disk 49 is nrounted in the mercury chamber inspaced relation with the end plate 25 and serves to narrow down themercury chamber and also to battle the waves or splashes of mercury soas to prevent the mercury seeping through the oint formed between thebushing 34 and plate 25.

The splash plate or disk 49 is composed of insulating material and isprovided with a peripheral rubber sealing ring 50 which forms a sealingconnection with the glass cylinder 29 forming the sides of the mercurychamber.

The end plate 27 is provided with a centrally arranged aperture in whicha shaft 51 is journaled having an arm 52 secured to its inner endcarrying a block 53 of wood or similar non-conducting material which isadapted to be inserted into or withdrawn from the mercury by rotation ofthe shaft 51 to raise or lower the level of the mercury. The shaft 51 isprovided with a worm-wheel 54, which is keyed thereto, and is meshedwith a worm 55 on a shaft 56 extending out beyond one side of theapparatus and provided with a hand wheel 57 by which it may be manuallyrotated to operate the shaft 51 and block 53.

The part of the flexible coupling 4 mounted 011 the spindle 38 includesa contact drum 85 through which the current from the interrupter 5 isdelivered to a brush contact 86. The motor 3 receives its power from theordinary house lines 58 and 59. The line 58 has the rheostat 6 connectedin series therewith and is connected to one pole of the motor. The line59 is connected to a switch 60 and a line 61 extends from the switch 60to the other pole of the motor. In operation, the speed of the motor,and consequently the speed of the mercury interrupter, is governed bythe operation of the rheostat 6.

The induced current applied to the patient is provided from a battery 62which has one pole connected by a line 62 to the base 26 of theinterrupter which is electrically connected with the mercury. The otherpole of the battery is connectedb-y a line 63 and switches 64, 65, and66 to the sliding contact arm 24 of the primary coil tap switch. Theswitch 64 is a supplemental switch used as an emergency circuit breaker.The switches 65 and 66 are adapted to be operated to open and close thecircuit to the primary coil during regular operation. The inner end ofthe primary coil is connected by a line 68 with the brush contact 86which receives the interrupted or alternating current from theinterrupter 5.

The induced current from the secondary winding passes through lines 70and 71 to any suitable form of applicator. The line 70 leads from theinner end of the secondary winding while the line 71 is connected to thesliding contact arm 24 of the secondary tap switch.

In operation, therheostat 6 is preferably adjusted so that the motor 3will operate the spindle 38 of the interrupter 5 at 1800 revolutions perminute, thereby causing the blade 45 to contact with the mercury 3600times per minute and the effect is that as the member or blade 45strikes the mercury, making sudden and complete contact, a magneticfield is built up with comparative rapidity in the inductance causingthe potential across the secondary winding to rise. During that; portionof the period of contact between the mercury and the blade 45, while theflow of primary current and the intensity of magnetic field ispractically constant, the induced potential begins to decrease. Owing,however, to the inductance or electrical inertia of the coil, the fallof the induced potential takes an appreciable time, and before itreaches zero value, the blade 45 leaves the mercury and interrupts theprimary current with the result that the magnetic field collapses, theinduced potential falls to zero, and owing to the collapsing field,changes its sign and again increases until the final and completeextinction of the magnetic field allows the induced potential to fall toand remain at zero value until a new cycle begins.

As the blade .45 leaves the mercury, the cessation of current flow isnot instantaneous owing largely to the fact that the blade carries withit a certain amount of mercury or mercury vapor which is drawn out andburns as a momentary mercury arc, thereby introducing a graduallyincreasing resistance into the primary circuit and preventing a suddencollapse of the magnetic field. This retarding effect on the collapse ofthe magnetic field prevents the excessive rise of induced potentialwhich would otherwise take place in the secondary circuit.

The form of the alternating current produced is of great importance. Theamplitude of the alternations of the current is a variable quantitydependent, among other things, upon the initial voltage across theprimary. coil and the amount of magnetic coupling between the windingsof the coil,.

but the form of the current is determined by the time intervals betweenmake and break in the primary circuit, the nature of theinterrupter,'the self induction of the coil, and other physicalconstants of the instrument.

The regulation of the induced secondary current, as applied to themuscles of the patient both in tlIIlSG and intensity, is effected andcontrolled by the insertion or withdrawal of the movable laminated coreof the coil. The operator is enabled to cause alternate painlesscontraction and relaxation of the muscle or group of muscles, and thetype of contraction produced so closely stimulates the physiologicalcontraction of a muscle, that the result is indistinguishable from anormal voluntary contraction.

The contraction produced is under the absolute control of the operator,and the rise and fall of the stimulus can be so accurately graduatedthat, starting from zero, it may be gradually increased 'to the maximumcontraction which the muscle acted -upon is capable of without damage,and the muscle then allowed to relax just as gradually, or, ifnecessary, it may be held in a state of contraction.

The contraction thus produced is in no way a local spasm of part 0 themuscle as is produced by the usual medical faradic coil, but

is a wave contraction of the entire length ofthe muscle. A singlemuscle, or a whole group of muscles, may be contracted and relaxed inthisway. A healthy group'of muscles, when acted upon by the a paratus ofthis invention, can thus be ma e to contract and relax rhythmically, soas to cause painless reproduction of the full movements of the joint 4upon which the particular group acts.

I claim: 1. In an electro medical apparatus for pro 'ducing alternatingcurrent adapted to cause muscular contraction on a patient under complete control of the operator, an inductance 0011, said 0011 comprisinga spool composed of of Number 18 gage, said winding having taps leadingfrom each layer thereof to contacts on the ends of said spool, a layerof insulating tape mounted over said primary winding, a secondarywinding wrapped on said layer of insulating tape and comprising aplurality of layers of double silk covered copper wire of Number 30gage, each layer of said secondary winding being separated by a layer ofinsulating tape, said seconda winding having a plurality of taps formeby loops of selected ones of the layers of said secondary windmg, saidtaps being connected to contacts on the ends of said spool, the one endof said primary winding being connected to an input contact on one endof said spool, and the one end of said secondary winding being connectedto an output contact on the other end. of said spool, a core tube formedof insulating material slidably mounted in said spool, a laminated coremounted in said tube and movable therewith, said core being adapted byits insertion into and withdrawal from the 0011 to regulate the inducedsecondary current.

2. In an electro medical apparatus for producing alternating currentadapted to cause muscular contraction on a patient, an nducance coil,and an interrupter 1n theprimary circuit of said coil, said interruptercomprising a cylindrical mercury chamber having lass side walls andmetal end walls, a shaft ournaled in the rear end wall and insulatedtherefrom, a double end contact blade mounted on 'the inner end of saidshaft andadapted to make and break contact with the mercury insaidchamber when said shaft is rotated, an insulating sleeve surroundingthe inner portion of said shaft, and an insulating support for the innerend of said shaft, a mercury level modifier comprising a block ofnonconducting material mounted in said chamber and adapted to be movedinto and out of the mercury to raise and lower the mercury level.

In testimony whereof, I have hereunto set my hand.

MORTON SMART, M. D. Cu. B.

